parse-datetime has the military time zones inverted

[Eigil Skjæveland]

Hi,

It seems the signs for the military time zones are inverted.

I would expect

date -d '12:00B'

to be equal to

date -d '12:00+0200'

but it is in fact equal to

date -d '12:00-0200'

This matches what I see in parse-datetime.y.